Regional differences in expression of TPH‐1, SERT, 5‐HT3 and 5‐HT4 receptors in the human stomach and duodenum

• Published in: Neurogastroenterology and motility Vol. 19; no. 5; pp. 342 - 348
• Main Authors: Van Lelyveld, N., Ter Linde, J., Schipper, M. E. I., Samsom, M.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.05.2007
• Subjects: gastroduodenal function; mRNA expression; serotonin
• ISSN: 1350-1925; 1365-2982
• DOI: 10.1111/j.1365-2982.2006.00891.x

The aim of this study was to increase the understanding of the role of serotonergic signalling in normal gastroduodenal function at a molecular level. Mucosal biopsy specimens were collected from the fundus, antrum and duodenum of 11 healthy subjects. Serotonin (5‐HT)‐positive cells were counted and the mRNA levels of tryptophan hydroxylase (TPH), serotonin transporter (SERT), 5‐HT4 receptor and 5‐HT3 receptor subunits were quantified by real‐time reverse transcription polymerase chain reaction. The number of 5‐HT‐positive cells was larger in the duodenum compared with the stomach (P < 0.001). Serotonin transport protein expression was 19‐fold higher in the duodenum compared with the antrum and 457‐fold higher compared with the fundus (P < 0.001). Tryptophan hydroxylase‐1 expression was lower in the duodenum compared with the antrum and fundus (regional differences −2.3 and −3.6, respectively). The 5‐HT4 receptor and the 5‐HT3C and 5‐HT3E receptor subunits were more abundantly expressed in duodenum compared with the stomach (P < 0.001). The larger number of 5‐HT‐positive cells, the higher expression of 5‐HT3 and 5‐HT4 receptors, and in particularly the higher uptake capacity of 5‐HT in the duodenum, point out to a more prominent role of serotonergic signalling at the mucosal level in the duodenum compared with the stomach.